An all-terrain vehicle includes a frame; four wheels; a suspension system; and a prime mover assembly. The frame includes auxiliary main beams which extend upwardly from a mid-height of one of the mid-rear pillars in a front tube section, and then angles from 120 to 170 to a longitudinal portion welded along its length to the upper main beam. The front tube sections each define a triangular shape together with the mid-rear pillars and the upper main beams. The all-terrain vehicle includes a front mounting bracket and two cargo rack structures, a cooling fan cover which supports several components of the cooling system, rear suspension swing arm mount plates formed of sheet metal, a passenger seat that elastically allows backrest lean angle changes, and a dual action brake caliper.